Journal Article

EAAT3 impedes oligodendrocyte remyelination in chronic cerebral hypoperfusion‐induced white matter injury

Wang, Jiawen, Ya, Dongshan, Li, Qinghua, Yang, Jiaxin, Deng, Jungang, Li, Xiaoxia, Jiang, Yanlin, Yang, Bin, Zhang, Yingmei, Liao, Rujia, Tian, Ning

2024

Overview

Background Chronic cerebral hypoperfusion‐induced demyelination causes progressive white matter injury, although the pathogenic pathways are unknown. Methods The Single Cell Portal and PanglaoDB databases were used to analyze single‐cell RNA sequencing experiments to determine the pattern of EAAT3 expression in CNS cells. Immunofluorescence (IF) was used to detect EAAT3 expression in oligodendrocytes and oligodendrocyte progenitor cells (OPCs). EAAT3 levels in mouse brains were measured using a western blot at various phases of development, as well as in traumatic brain injury (TBI) and intracerebral hemorrhage (ICH) mouse models. The mouse bilateral carotid artery stenosis (BCAS) model was used to create white matter injury. IF, Luxol Fast Blue staining, and electron microscopy were used to investigate the effect of remyelination. 5‐Ethynyl‐2‐Deoxy Uridine staining, transwell chamber assays, and IF were used to examine the effects of OPCs' proliferation, migration, and differentiation in vivo and in vitro. The novel object recognition test, the Y‐maze test, the rotarod test, and the grid walking test were used to examine the impact of behavioral modifications. Results A considerable amount of EAAT3 was expressed in OPCs and mature oligodendrocytes, according to single‐cell RNA sequencing data. During multiple critical phases of mouse brain development, there were no substantial changes in EAAT3 levels in the hippocampus, cerebral cortex, or white matter. Furthermore, neither the TBI nor ICH models significantly affected the levels of EAAT3 in the aforementioned brain areas. The chronic white matter injury caused by BCAS, on the other hand, resulted in a strikingly high level of EAAT3 expression in the oligodendroglia and white matter. Correspondingly, blocking EAAT3 assisted in the recovery of cognitive and motor impairment as well as the restoration of cerebral blood flow following BCAS. Furthermore, EAAT3 suppression was connected to improved OPCs' survival and proliferation in vivo as well as faster OPCs' proliferation, migration, and differentiation in vitro. Furthermore, this study revealed that the mTOR pathway is implicated in EAAT3‐mediated remyelination. Conclusions Our findings provide the first evidence that abnormally high levels of oligodendroglial EAAT3 in chronic cerebral hypoperfusion impair OPCs' pro‐remyelination actions, hence impeding white matter repair and functional recovery. EAAT3 inhibitors could be useful in the treatment of ischemia demyelination. We show for the first time that (1) EAAT3 impairs OPC differentiation, migration, and proliferation; (2) EAAT3 suppression for these OPCs aid in the survival of oligodendroglia, remyelination of white matter, and ultimately functional recovery; (3) the phosphorylated mTOR pathway facilitates remyelination and white matter repair through EAAT3 suppression. These results suggest that EAAT3‐targeting strategies may be therapeutically useful for treating demyelinating illnesses.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Anesthesia / Animal cognition / Animal models / Animals / Blood flow / Brain Injuries, Traumatic - metabolism / Brain Ischemia - metabolism / Carotid arteries / Carotid artery / Carotid Stenosis - pathology / Cerebral blood flow / Cerebral cortex / chronic cerebral hypoperfusion / Cognitive ability / Demyelinating Diseases - pathology / Demyelination / Electron microscopy / excitatory amino acid transporter 3 (EAAT3) / Excitatory amino acid transporters / Glial stem cells / Hemorrhage / Immunofluorescence / Ischemia / Laboratory animals / Life sciences / Mice / Mice, Inbred C57BL / Myelination / neuroprotection / oligodendrocyte progenitor cells (OPCs) / Oligodendrocytes / Oligodendroglia - metabolism / Original / Pattern recognition / Progenitor cells / Recovery of function / Remyelination / Stenosis / Stroke / Substantia alba / Surgery / TOR protein / Traumatic brain injury / Uridine / white matter / White Matter - pathology